Convert Imperial Gallon to Cubic Inch
Convert imperial gallons to cubic inches instantly. 1 imperial gallon = 277.4194327916 cubic inch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Cubic Inch to Imperial Gallon converter for the reverse conversion.
Units explained
Imperial Gallon
The imperial gallon is defined as exactly 4.54609 liters.
Set by the British Weights and Measures Act of 1824 as the volume of 10 lb of water.
Used for fuel and beverages in the UK and Commonwealth.
UK, 1824.
Cubic Inch
A cubic inch is the volume of a cube one inch on a side (16.387 mL).
Derived by cubing the international inch (25.4 mm).
Used for engine displacement and small-part volumes.
1959 yard agreement.
Imperial Gallon to Cubic Inch conversion formula
The relationship between imperial gallons and cubic inches:
To convert imperial gallons to cubic inches, multiply the value in imperial gallons by 277.4194327916. To reverse, multiply cubic inches by 0.0036046501.
How to use this converter
Type a value into the calculator. The result in cubic inches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Cubic Inch to Imperial Gallon converter for the reverse direction.
Step-by-step: convert imperial gallons to cubic inches
- Write down the value in imperial gallons (gal).
- Multiply that value by the factor 277.4194327916.
- The product is the equivalent value in cubic inches (in³).
- To reverse, multiply the cubic inch value by 0.0036046501.
Worked examples
Example 1 — Convert 1 gal to in³:
1 × 277.4194327916 = 277.4194327916 in³
Example 2 — Convert 100 gal to in³:
100 × 277.4194327916 = 27741.9432791621 in³
Real-world example — Adjacent metric sub-units
One imperial gallon equals 1,000 cubic inches. Engineers move between these scales constantly: PCB feature sizes in the larger unit, wire-bond diameters in the smaller.
1 gal × 277.4194327916 = 277.4194327916 in³
Real-world example — Adjacent small-scale precision
One imperial gallon equals 1,000 cubic inches — the standard sub-millimeter precision conversion that materials engineers use whenever they switch between bulk material thickness specs (larger unit) and surface-finish characteristics (smaller unit).
1 gal × 277.4194327916 = 277.4194327916 in³
Imperial Gallon to Cubic Inch conversion table
Standard reference values for converting imperial gallons to cubic inches:
| Imperial Gallon [gal] | Cubic Inch [in³] |
|---|---|
| 0.01 | 2.7741943279 |
| 0.1 | 27.7419432792 |
| 1 | 277.4194327916 |
| 2 | 554.8388655832 |
| 3 | 832.2582983749 |
| 4 | 1109.6777311665 |
| 5 | 1387.0971639581 |
| 10 | 2774.1943279162 |
| 20 | 5548.3886558324 |
| 30 | 8322.5829837486 |
| 40 | 11096.7773116649 |
| 50 | 13870.9716395811 |
| 100 | 27741.9432791621 |
| 500 | 138709.7163958107 |
| 1000 | 277419.4327916215 |
Frequently asked questions
How many cubic inches is 1 imperial gallon?
How do I convert imperial gallons to cubic inches?
How do I convert cubic inches back to imperial gallons?
How many cubic inches is 100 imperial gallons?
Popular volume unit conversions
Convert Imperial Gallon to other volume units
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Metric / SI (15 units)
US Customary (Liquid) (15 units)
US Customary (Dry) (5 units)
Imperial (UK) (13 units)
Cubic (length-derived) (4 units)
Cooking / Culinary (5 units)
Sources & references
Conversion factor (1 gal = 277.4194327916 in³) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.